Abstract: The Li-rich Mn-based cathode material Li1.133Mn0.466Ni0.2Co0.2O2 was successfully synthesized via a facile co-precipitation method. Detailedly speaking, the metal acetates Mn(AC)24H2O, Ni(AC)24H2O and Co(AC)24H2O with a stoichiometric?ratio were completely dissolved in deionized water to form a homogeneous aqueous solution. Then, Na2CO3 solution as precipitant agent was added to prepare the precursor Mn0.466Ni0.2Co0.2CO3. Finally, the precursor was mixed and ground with Li2CO3 and LiOHH2O respectively, followed by a high-temperature calcination process to obtain the material (Li1.133Mn0.466Ni0.2Co0.2O2). The crystal structure and surface morphology of the as-prepared products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Besides, the electrochemical performances were measured using galvanostatic charge-discharge technique and cyclic voltammetry. The results show that the sample mixing with LiOHH2O delivers the charge and discharge capacity of 330.1mAh/g and 218.6mAh/g at 0.1C (1C = 250 mA/g) with a coulomb efficiency of 66.23%. Besides, it exhibits better cycling stability and rate capability at 1C, but worse at 2C or even higher rates as compared to the sample mixing with Li2CO3.